Effect of Winged Subsoiler and Traditional Tillage Integrated with <i>Fanya Juu</i> on Selected Soil Physico-Chemical and Soil Water Properties in the Northwestern Highlands of Ethiopia

Abstract

Prolonged water-logging, soil degradation and decline in water productivity due to hard pans created because of repeated cross plowing using the traditional plow is the major problem in the northwestern highlands of Ethiopia. To reduce these problems, alternative tillage and soil management practices have to be implemented. Thus, the effects of winged subsoiler and traditional tillage practices on tillage depth, bulk density, infiltration, and soil moisture conditions were assessed in an on-farm experimental study in the northwestern highlands of Ethiopia. The experiment was laid out in a randomized complete block design (RCBD) with two treatments (winged subsoiler and traditional tillage) and four replicates. The study was conducted from 2011 to 2012 cropping seasons. Soil samples were collected from 0-10, 10-20, 20-30 and 50-60 cm of soil depths and analyzed for bulk density, soil texture and organic matter contents. Soil moisture was measured using 10HS automatic soil moisture sensors (CaTecR) which were inserted at 10 cm depth under both tillage types. Four readings, once every week were taken both at the lower and upper parts of the plots. Using the double ring infiltrometer, infiltration measurements were made in the experimental units treated by both tillage practices. Soil evaporation was estimated by a conceptual model whereby leaf area index, canopy cover, crop root length, moisture at saturation and field capacity were used as inputs. Substantially higher tillage depths were observed due to the winged subsoiler while dry bulk density was slightly higher in the traditional tillage. Significantly (P . 0.05) different soil moisture contents between the upper and lower sides of the fanya juus were observed under traditional tillage practice (0.305}0.003 and 0.323}0.003 m3 m-3, respectively). Infiltration rate and cumulative infiltration in the winged subsoiler treated plots exceeded that of the traditionally plowed plots. Compared with the traditional tillage, the winged subsoiler treated plots resulted in better moisture retention, high infiltration, high tillage depth and low soil evaporation. The result indicated that if the winged subsoiler is properly implemented and integrated with fanya juu, it is an important and effective conservation practice for sustainable soil and water management for smallholder farmers in the northwestern Ethiopia.

Keywords: Ethiopia; Plow Pan; Soil Moisture; Traditional Tillage; Winged Subsoiler